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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-16 19:23:18 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-16 19:23:18 +0000 |
commit | 43a123c1ae6613b3efeed291fa552ecd909d3acf (patch) | |
tree | fd92518b7024bc74031f78a1cf9e454b65e73665 /src/bytes/compare_test.go | |
parent | Initial commit. (diff) | |
download | golang-1.20-upstream.tar.xz golang-1.20-upstream.zip |
Adding upstream version 1.20.14.upstream/1.20.14upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/bytes/compare_test.go')
-rw-r--r-- | src/bytes/compare_test.go | 271 |
1 files changed, 271 insertions, 0 deletions
diff --git a/src/bytes/compare_test.go b/src/bytes/compare_test.go new file mode 100644 index 0000000..a0150ab --- /dev/null +++ b/src/bytes/compare_test.go @@ -0,0 +1,271 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package bytes_test + +import ( + . "bytes" + "fmt" + "internal/testenv" + "testing" +) + +var compareTests = []struct { + a, b []byte + i int +}{ + {[]byte(""), []byte(""), 0}, + {[]byte("a"), []byte(""), 1}, + {[]byte(""), []byte("a"), -1}, + {[]byte("abc"), []byte("abc"), 0}, + {[]byte("abd"), []byte("abc"), 1}, + {[]byte("abc"), []byte("abd"), -1}, + {[]byte("ab"), []byte("abc"), -1}, + {[]byte("abc"), []byte("ab"), 1}, + {[]byte("x"), []byte("ab"), 1}, + {[]byte("ab"), []byte("x"), -1}, + {[]byte("x"), []byte("a"), 1}, + {[]byte("b"), []byte("x"), -1}, + // test runtime·memeq's chunked implementation + {[]byte("abcdefgh"), []byte("abcdefgh"), 0}, + {[]byte("abcdefghi"), []byte("abcdefghi"), 0}, + {[]byte("abcdefghi"), []byte("abcdefghj"), -1}, + {[]byte("abcdefghj"), []byte("abcdefghi"), 1}, + // nil tests + {nil, nil, 0}, + {[]byte(""), nil, 0}, + {nil, []byte(""), 0}, + {[]byte("a"), nil, 1}, + {nil, []byte("a"), -1}, +} + +func TestCompare(t *testing.T) { + for _, tt := range compareTests { + numShifts := 16 + buffer := make([]byte, len(tt.b)+numShifts) + // vary the input alignment of tt.b + for offset := 0; offset <= numShifts; offset++ { + shiftedB := buffer[offset : len(tt.b)+offset] + copy(shiftedB, tt.b) + cmp := Compare(tt.a, shiftedB) + if cmp != tt.i { + t.Errorf(`Compare(%q, %q), offset %d = %v; want %v`, tt.a, tt.b, offset, cmp, tt.i) + } + } + } +} + +func TestCompareIdenticalSlice(t *testing.T) { + var b = []byte("Hello Gophers!") + if Compare(b, b) != 0 { + t.Error("b != b") + } + if Compare(b, b[:1]) != 1 { + t.Error("b > b[:1] failed") + } +} + +func TestCompareBytes(t *testing.T) { + lengths := make([]int, 0) // lengths to test in ascending order + for i := 0; i <= 128; i++ { + lengths = append(lengths, i) + } + lengths = append(lengths, 256, 512, 1024, 1333, 4095, 4096, 4097) + + if !testing.Short() || testenv.Builder() != "" { + lengths = append(lengths, 65535, 65536, 65537, 99999) + } + + n := lengths[len(lengths)-1] + a := make([]byte, n+1) + b := make([]byte, n+1) + for _, len := range lengths { + // randomish but deterministic data. No 0 or 255. + for i := 0; i < len; i++ { + a[i] = byte(1 + 31*i%254) + b[i] = byte(1 + 31*i%254) + } + // data past the end is different + for i := len; i <= n; i++ { + a[i] = 8 + b[i] = 9 + } + cmp := Compare(a[:len], b[:len]) + if cmp != 0 { + t.Errorf(`CompareIdentical(%d) = %d`, len, cmp) + } + if len > 0 { + cmp = Compare(a[:len-1], b[:len]) + if cmp != -1 { + t.Errorf(`CompareAshorter(%d) = %d`, len, cmp) + } + cmp = Compare(a[:len], b[:len-1]) + if cmp != 1 { + t.Errorf(`CompareBshorter(%d) = %d`, len, cmp) + } + } + for k := 0; k < len; k++ { + b[k] = a[k] - 1 + cmp = Compare(a[:len], b[:len]) + if cmp != 1 { + t.Errorf(`CompareAbigger(%d,%d) = %d`, len, k, cmp) + } + b[k] = a[k] + 1 + cmp = Compare(a[:len], b[:len]) + if cmp != -1 { + t.Errorf(`CompareBbigger(%d,%d) = %d`, len, k, cmp) + } + b[k] = a[k] + } + } +} + +func TestEndianBaseCompare(t *testing.T) { + // This test compares byte slices that are almost identical, except one + // difference that for some j, a[j]>b[j] and a[j+1]<b[j+1]. If the implementation + // compares large chunks with wrong endianness, it gets wrong result. + // no vector register is larger than 512 bytes for now + const maxLength = 512 + a := make([]byte, maxLength) + b := make([]byte, maxLength) + // randomish but deterministic data. No 0 or 255. + for i := 0; i < maxLength; i++ { + a[i] = byte(1 + 31*i%254) + b[i] = byte(1 + 31*i%254) + } + for i := 2; i <= maxLength; i <<= 1 { + for j := 0; j < i-1; j++ { + a[j] = b[j] - 1 + a[j+1] = b[j+1] + 1 + cmp := Compare(a[:i], b[:i]) + if cmp != -1 { + t.Errorf(`CompareBbigger(%d,%d) = %d`, i, j, cmp) + } + a[j] = b[j] + 1 + a[j+1] = b[j+1] - 1 + cmp = Compare(a[:i], b[:i]) + if cmp != 1 { + t.Errorf(`CompareAbigger(%d,%d) = %d`, i, j, cmp) + } + a[j] = b[j] + a[j+1] = b[j+1] + } + } +} + +func BenchmarkCompareBytesEqual(b *testing.B) { + b1 := []byte("Hello Gophers!") + b2 := []byte("Hello Gophers!") + for i := 0; i < b.N; i++ { + if Compare(b1, b2) != 0 { + b.Fatal("b1 != b2") + } + } +} + +func BenchmarkCompareBytesToNil(b *testing.B) { + b1 := []byte("Hello Gophers!") + var b2 []byte + for i := 0; i < b.N; i++ { + if Compare(b1, b2) != 1 { + b.Fatal("b1 > b2 failed") + } + } +} + +func BenchmarkCompareBytesEmpty(b *testing.B) { + b1 := []byte("") + b2 := b1 + for i := 0; i < b.N; i++ { + if Compare(b1, b2) != 0 { + b.Fatal("b1 != b2") + } + } +} + +func BenchmarkCompareBytesIdentical(b *testing.B) { + b1 := []byte("Hello Gophers!") + b2 := b1 + for i := 0; i < b.N; i++ { + if Compare(b1, b2) != 0 { + b.Fatal("b1 != b2") + } + } +} + +func BenchmarkCompareBytesSameLength(b *testing.B) { + b1 := []byte("Hello Gophers!") + b2 := []byte("Hello, Gophers") + for i := 0; i < b.N; i++ { + if Compare(b1, b2) != -1 { + b.Fatal("b1 < b2 failed") + } + } +} + +func BenchmarkCompareBytesDifferentLength(b *testing.B) { + b1 := []byte("Hello Gophers!") + b2 := []byte("Hello, Gophers!") + for i := 0; i < b.N; i++ { + if Compare(b1, b2) != -1 { + b.Fatal("b1 < b2 failed") + } + } +} + +func benchmarkCompareBytesBigUnaligned(b *testing.B, offset int) { + b.StopTimer() + b1 := make([]byte, 0, 1<<20) + for len(b1) < 1<<20 { + b1 = append(b1, "Hello Gophers!"...) + } + b2 := append([]byte("12345678")[:offset], b1...) + b.StartTimer() + for j := 0; j < b.N; j++ { + if Compare(b1, b2[offset:]) != 0 { + b.Fatal("b1 != b2") + } + } + b.SetBytes(int64(len(b1))) +} + +func BenchmarkCompareBytesBigUnaligned(b *testing.B) { + for i := 1; i < 8; i++ { + b.Run(fmt.Sprintf("offset=%d", i), func(b *testing.B) { + benchmarkCompareBytesBigUnaligned(b, i) + }) + } +} + +func BenchmarkCompareBytesBig(b *testing.B) { + b.StopTimer() + b1 := make([]byte, 0, 1<<20) + for len(b1) < 1<<20 { + b1 = append(b1, "Hello Gophers!"...) + } + b2 := append([]byte{}, b1...) + b.StartTimer() + for i := 0; i < b.N; i++ { + if Compare(b1, b2) != 0 { + b.Fatal("b1 != b2") + } + } + b.SetBytes(int64(len(b1))) +} + +func BenchmarkCompareBytesBigIdentical(b *testing.B) { + b.StopTimer() + b1 := make([]byte, 0, 1<<20) + for len(b1) < 1<<20 { + b1 = append(b1, "Hello Gophers!"...) + } + b2 := b1 + b.StartTimer() + for i := 0; i < b.N; i++ { + if Compare(b1, b2) != 0 { + b.Fatal("b1 != b2") + } + } + b.SetBytes(int64(len(b1))) +} |